WASHINGTON — When the establishment told him he should talk with North Korea, President Trump scorned the idea. “Presidents and their administrations have been talking to North Korea for 25 years” and had been made to look like “fools,” he scoffed, and then rattled his saber. “Sorry, but only one thing will work!”

Five months later, Mr. Trump cast aside his skepticism and agreed to talk to North Korea with no more promise of success at negotiating an end to its nuclear and missile programs than his predecessors had. The main difference this time around is who will do the talking for the United States: Donald J. Trump.

Shocking and yet somehow not surprising, Mr. Trump’s decision to do what no other sitting president has done and meet in person with a North Korean leader reflects an audacious and supremely self-confident approach to international affairs. Whether it is Middle East peace or trade agreements, Mr. Trump has repeatedly claimed that he can achieve what has eluded every other occupant of his office through the force of his own personality.

So far, he has little to show for that. He has yet to successfully negotiate any new trade deals or renegotiate any old ones. A resolution between Israel and the Palestinians, which he once said would be “maybe not as difficult as people have thought,” looks more distant than when he came into office. Beyond threatening “fire and fury,” he has offered no original formula that suggests a path to unlock the North Korea puzzle.

Here are three key moments when negotiations between the United States and North Korea have appeared successful — but didn’t stick.Published OnMarch 6, 2018CreditCreditDoug Mills/The New York Times

“In some ways there’s a symmetry,” said Wendy R. Sherman, a longtime former diplomat who was part of a historic American delegation to Pyongyang under President Bill Clinton and later negotiated the Iran nuclear agreement for President Barack Obama. “You have two leaders who believe fundamentally that they are the only people who matter.”

Other presidents left talks with North Korea to lower-level officials because they did not want to reward Pyongyang with the prestige of such a meeting unless there was a substantial assurance of a breakthrough. They feared an ill-conceived gathering that resulted in failure would be counterproductive.

Mr. Clinton considered going to Pyongyang in the twilight months of his presidency, but ultimately opted against it, partly because of the Florida recount that dominated the postelection period in 2000 and partly because he calculated he had a better chance of forging an agreement between Israel and the Palestinians in the time he had left. He was unable to achieve that either, but after leaving office, went to North Korea to bring home two Americans held prisoner.

Diplomacy is a positive, Ms. Sherman said. “But this is a diplomacy that has to be prepared. It’s why Bill Clinton didn’t drop everything and go to Pyongyang.” She added: “This is very serious business. It is not a reality show. And it’s our national security that is at stake.”

While the president’s economic pressure may have prompted him to come to the table, Mr. Kim made few known concessions to win a meeting with Mr. Trump. The North Korean leader agreed to suspend nuclear and missile tests for the moment, although after a year of accelerated tests, they may not be as necessary for the program’s development at this point. And he assented to routine joint military exercises by the United States and South Korea that usually draw his ire.

“I can’t imagine any other president doing this on the basis of these general comments passed on from Kim Jong-un,” said Christopher R. Hill, who negotiated with North Korea for President George W. Bush. “The question is whether Trump will go ahead without clear signs the North Koreans are on the way to denuclearization.”

Among those surprised by the president’s decision to meet Mr. Kim were some of his own advisers. “In terms of direct talks with the United States, you ask negotiations and we’re a long ways from negotiations,” Secretary of State Rex W. Tillerson told reporters traveling with him in Africa just hours before the surprise announcement at the White House.

But the president has flirted with the idea of meeting Mr. Kim before, and James Jay Carafano, a national security scholar at the Heritage Foundation, said it was utterly predictable that Mr. Trump would want to personally take on the issue.

“Trump actually has a really good track record of talking to other leaders,” Mr. Carafano said. “We ought to get beyond this thing that he’s going to be stupid. He’s now met with dozens of world leaders. This is actually where he shines, meeting with other leaders and looking very presidential. The fact that he would want to look the guy in the eye is very Trumpian.”

Indeed, Mr. Trump has been far more eager to deal directly with foreign leaders than Mr. Obama, a hands-on interlocutor who has forged relationships that changed his views and policies, such as with President Xi Jinping of China.

Mr. Carafano said Mr. Trump, the first president never to have served in government or the military, is not wedded to stale nostrums and is willing to think outside the box. He cited Mr. Trump’s decision to recognize Jerusalem as Israel’s capital, a move Democratic and Republican presidents were too wary to make. While it drew loud protests from Palestinians, Mr. Carafano said, the world did not come to an end.

But Mr. Carafano cautioned against expecting a breakthrough if the meeting with Mr. Kim takes place. “The odds of him actually negotiating something are incredibly small,” he said. But the president’s agreement to talk dispels the warnings by critics that Mr. Trump was inevitably headed to war with North Korea through his bellicose messaging. “Our policy is not on this inevitable path to World War III.”

Still, the critics remain dubious. While they have urged Mr. Trump to try diplomacy, many said they did not mean that he should do it personally, and they warned that the president did not seem to have a thought-through plan for what he could reasonably achieve and how he would do it. Given Mr. Trump’s repeated criticism of Mr. Obama’s Iran deal — and a looming deadline for deciding whether to scrap it — the president would be hard pressed to agree to any accord with North Korea that fell short of its terms.

“Trump sees himself as a master negotiator, and yet is not particularly good at it,” said Colin Kahl, a former national security official under Mr. Obama. “He isn’t thoughtful or steeped in the types of details required for this type of diplomacy. He is prone to manipulation and flattery. He often makes threats he doesn’t follow through on and promises he can’t or won’t keep. And he often throws allies under the bus. This does not add up to a recipe for success, and the stakes could not be higher.”

But the president’s aides said he was full of surprises and should not be discounted. While noting that this would be a meeting, not a negotiation, a senior administration official, who briefed reporters on the condition of anonymity, said Mr. Trump was elected in part because he was willing to take approaches different from those of other presidents, a trait best exemplified by his North Korea policy.

Mr. Kim is the undisputed master of his totalitarian system, the official said, and so it made sense to accept an invitation to meet with the one person who can actually make decisions instead of repeating the long slog of the past.

The real question, then, becomes whether the only two leaders who can make decisions can make one together.